The present invention relates to a method of storing photographic processing solutions used for treating silver halide photographic light-sensitive materials of color photography, and more specifically to a method to store color developer as well as bleach-fixer without deteriorating the properties of such processing solutions.
Generally, forming a photographic image inevitably accompanies a process to form a negative or positive image by treating a silver halide photographic light-sensitive material already bearing a latent image in such processing steps as developing, fixing and the like. With a silver halide photographic light-sensitive material for color photography, a negative or positive color image is formed via such processes as color developing, bleach-fixing (in some cases, bleaching and fixing are independently carried out), washing and others.
Treating silver halide photographic light-sensitive materials in such processes has been conventionally exercised in photofinishing laboratories, known as large-scale laboratory systems having large-scale facilities and equipment. Recently however, the chances are increasing for less experienced people, or so-called "amateurs", to process silver halide photographic light-sensitive materials, as the so-called mini-laboratory systems for private use, which allow easy processing even in individual camera shops, business offices and the like, have been developed and marketed. Developing and bleach-fixing the silver halide photographic light-sensitive materials for color photography requires color developer and bleach-fixer. In such processing steps for the so-called mini-laboratory system for private use, these processing solutions should be readily-usable types having incorporated specific ingredients, because an operator is a so-called "amateur".
However, the conventional color developer comprises contents working as oxidizing agents as well as those working as reducing agents. Accordingly, such a developer has disadvantages: its properties tend to deteriorate due to internal redox reaction during storage; reductive materials in it tends to degrade due to oxidation with air. As a result, the long-term storage of the similar developer is disadvantageously difficult.
As a useful bleach-fixer, those composed of ferric aminocarboxylate and thiosulfate have been conventionally known in the art. However, such a bleach-fixer has a problem; because ferric aminocarboxylate functions as an oxidizing agent, and thiosulfate functions as a reducing agent, the thiosulfate is decomposed in oxidation by the ferric aminocarboxylate during the course of storing the bleach-fixer, generating sulfur, and, consequently, the properties of the bleach-fixer deteriorates as the sulfur precipitates.
Therefore, an arrangement to incorporate sulfite, as a preservative to inhibit oxidation-decomposition of thiosulfate, into a bleach-fixer is exercised. Sulfite, however, is readily decomposed by oxygen in air, and is readily oxidized with the ferric aminocarboxylate. Accordingly, the proportion of sulfite gradually decreaes in the course of storage of bleachfixer, and the sulfite gradually fails to fully provide its performance as a preservative, thus, making the long-term preservation of bleach-fixer difficult.
Accordingly, the color developer and the bleach-fixer have been supplied to users in compliance with the following means
(1) A supplying means, whereby each of such processing solutions prepared by experts in the photofinishing laboratories known as large-scale laboratory systems is supplied in a small quantity to a user immediately before the actual use. PA1 (2) A supplying means, whereby each of such processing solutions is supplied to a user, in the form of a kit comprising packages each containing a pack of each ingredient.
With a means in (1), above, however, it is significantly difficult to swiftly and smoothly deliver necessary amounts of the prepared processing solutions, above, to a user immediately before the actual use, because a user operating a mini-laboratory system does not know either when the order for photographic processing will come, nor how large is the size of order, or, even worse, the user may fail to produce photographs within a period in compliance with an order from a client, because of the delay in supply of the above-mentioned processing solutions. On the other hand, it seems possible to order rather larger amounts of such processing solutions in advance, by estimating necessary amounts. Such a precaution, however, disadvantageously causes the deterioration of properties for the above-mentioned processing solutions.
The means in (2), above, involves many ingredients which must be prepared, and also requires a procedure to dissolve the ingredients into a solvent. Furthermore, in this procedure, it is usually mandatory to start dissolving one ingredient after another ingredient has been completely dissolved. This indicates one must wait, with continuous stirring, for several to scores of minutes before one can start dissolving another ingredient, and, therefore, requires considerable amount of time and labor. Since an operator who operates a mini-laboratory system for private use, installed in a camera shop, business office or the like, is usually a layman in photographic processing, he/she has a difficulty in identifying ingredients separately packed, and may incorrectly prepare the above-mentioned processing solutions, and therefore may fail to prepare the above-mentioned processing solutions, that is, color developer and bleach-fixer respectively having adequate photographic performance.
For this reason, the inventors have devoted themselves in the study of a container which stores color developer or bleach-fixer free from the property deterioration of such a processing solution.
As a one means for this purpose, it is possible to store a color developer in a sealed container comprising a plastic packing material having extremely low permeability to oxygen, so as to prevent this processing solution from being deteriorated in properties by oxidation.
A color developer, however, conventionally contains a preservative, such as a hydroxylamine, or a sulfate or hydrochloride thereof, which prevents the oxidation by air and inhibits redox reaction among ingredients. Such a hydroxylamine readily decomposes in an alkali solution, and readily emits ammonia gas and nitrogen gas, causing various problems: the color developer may fail to fully provide its photographic performance; the nitrogen gas filled in a sealed container may break a seal of a plastic packing material, leaking the color developer, or may break an outlet or inlet for color developer provided on the container.
In contrast, it is possible to diffuse nitrogen gas generated in a container composed of a plastic packing material through which nitrogen gas can readily permeate. This arrangement however invites another problem; oxygen gas permeates into the container, causing the color developer to deteriorate due to oxidation.
Additionally, a means was already proposed, wherein generation of nitrogen gas is inhibited by storing a color developer in the form of condensed paste, and during a developing process the developer is taken out of the container in a specific amount which is automatically dissolved into water (see the specifications of PCT-designated Japanese Patent Publications Nos. 500487/1982 and 500485/1982).
Such a technical means, however, poses a problem; being stored in a container in the form of condensed paste, the color developer tends to be highly alkali, and is readily air-oxidized, and, its properties prematurely deteriorate due to a redox reaction.
Consequently, in practice, a color developing agent, a preservative comprising hydroxylamine, and an alkali agent are necessarily stored in independent packs. Accordingly, a user himself/herself must blend the ingredients to prepare a color developer before carrying out developing process.
Though being excellent in the performance, as a preservative, an unsubstituted hydroxylamine, or a sulfate thereof, has a strong toxity, and has a large probability to adversely affect human body or the like when a user handles a color developer in a mini-laboratory system for the private use.
The method of storing a color developer, wherein a color developer not requiring a procedure to blend the necessary ingredient and being safe in handling because having small toxity is stably stored for a longer period, has not yet found.
In the case of a bleach-fixer, it seems possible to store the bleach fixer being sealed in a container comprising a plastic packing material having an extremely low oxygen-permeability, so as to prevent the property deterioration of the bleach-fixer due to air-oxidation.
However, despite such arrangement, the oxidation of sulfite in the bleach-fixer processed due to a trifle amount of oxygen permeating through the container, and the oxidation further proceeds by ferric aminocarboxylate in the bleach-fixer As a result, the sulfide fails to fully provide its performance as a preservative, triggering the oxygenic decomposition of thiosulfate, which lowers the performance of the bleach-fixer. Additionally, the oxidation of sulfite in bleach-fixer by ferric aminocarboxylate generates ferrous aminocarboxylate as a reduction product of the ferric aminocarboxylate generates, and the cumulative ferrous aminocarboxylate disadvantageously causes so-called poor recoloration, wherein a dye is made into a leuco material which has a color different from that of the dye.
As can be understood from the description, above, storing a bleach-fixer for a longer period in a container composed of a plastic packing material having a small oxygen-permeation coefficient will cause a problem of the poor recoloration, mentioned above. On the other hand, storing a bleach-fixer for a longer period in a container composed of a plastic packing material having a large oxygen-permeation coefficient will cause oxygen-decomposition of sulfite and thiosulfate, deteriorating the performance of bleach-fixer; the phenomenon where both types of storing conflict with each other.
In view of such drawbacks, having devotedly studied the solutions, the inventors have reached the following findings, which in turn have realized the present invention:
By regulating the proportion of contained aminopolycarboxylic acid which is a free chelating agent usually contained in a bleach-fixer and serving as a stabilizing agent for ferric aminopolycarboxylate, a bleach-fixer can be stably stored without incurring the problems such as the failure in recoloration, mentioned above, even if the bleach-fixer is stored for an extended period in a container composed of a plastic packing material having a small oxygen-permeation coefficient, and; by selecting a content of contained sulfite in proportion of content of contained aminopolycarboxylic acid, mentioned above, the decomposition of the sulfite can be considerably inhibited.